WO2011077825A1

WO2011077825A1 - Liquid crystal display device, drive method of liquid crystal display device, and electronic device

Info

Publication number: WO2011077825A1
Application number: PCT/JP2010/068756
Authority: WO
Inventors: 尚宏山口; 高橋　功; 業天　誠二郎; 松田　登
Original assignee: シャープ株式会社
Priority date: 2009-12-24
Filing date: 2010-10-22
Publication date: 2011-06-30
Also published as: US20120287110A1; JPWO2011077825A1

Abstract

Provided is a liquid crystal display device in which, in the case where a period during which a voltage corresponding to a video signal supplied to a source bus line (Sn) is applied to a pixel electrode (101) is set as a write period of the video signal, and a period until the write period of the next video signal is set as a non-write period of the video signal, an in-phase signal or a reverse phase signal of a signal supplied to an opposite electrode (103) is supplied to the source bus line (Sn) during the non-write period. As a result, it becomes possible to keep a potential difference caused between the source bus line (Sn) and the opposite electrode (103) constant. Thus, a flicker caused between the source bus line and the opposite electrode is prevented, thereby achieving a liquid crystal display device having high display quality.

Description

Liquid crystal display device, driving method of liquid crystal display device, and electronic apparatus

The present invention relates to a liquid crystal display device having a memory function.

In recent years, in mobile terminals typified by mobile phones, an increase in power consumption due to multi-function has become a problem. Therefore, in order to reduce power consumption even a little in the portable terminal, power saving is achieved in a liquid crystal display device that constitutes a display unit that consumes particularly high power.

In a liquid crystal display device, in order to reduce power consumption, for example, when displaying a screen with little image change such as a time display on a mobile phone, a video signal is supplied to a liquid crystal capacitor in a pixel formation unit for displaying pixels. The writing cycle is lengthened.

However, if the writing period of the video signal to the liquid crystal capacitor is lengthened, the applied voltage must be held for a long time in the liquid crystal capacitor. For this reason, in the liquid crystal display device as described above, a circuit having a memory function (hereinafter referred to as a pixel memory circuit) is provided in each pixel formation portion so that the voltage applied to the liquid crystal capacitance is maintained. Yes.

Examples of the liquid crystal display device incorporating such a pixel memory circuit include the display device disclosed in Patent Document 1.

Japanese Patent Publication “JP 2007-286237 (published Nov. 1, 2007)”

By the way, in a general liquid crystal display device, a source bus line is provided between pixel electrodes, and a black matrix is formed on the source bus line, resulting in a potential difference generated between the source bus line and the counter electrode. Thus, the flicker on the source bus line can be hidden from being seen by the black matrix.

However, as described above, it is possible to hide the flicker on the source bus line by the black matrix, but in the case where the black matrix is not provided, the potential difference generated between the source bus line and the counter electrode. If is not constant, flicker will be visible.

Also, even if a black matrix is provided on the source bus line, flicker generated on the source bus line can be seen if it is not provided at a proper position. That is, if flicker occurs on the source bus line, the flicker may be seen even if a black matrix is provided.

Usually, the pixel electrode 101 and the counter electrode 103 are applied with a signal (voltage) that is inverted at a constant period so that the liquid crystal is not deteriorated. For example, as shown in FIG. 5A, in-phase or anti-phase signals are applied to the pixel electrode 101 and the counter electrode 103 so as to always have a constant potential difference. In the example shown in FIG. 5A, the voltage applied to the liquid crystal interposed between the pixel electrode 101 and the counter electrode 103, that is, the liquid crystal applied voltage is 0 V (white display: normally white). Case). For this reason, flicker due to a variation in potential difference does not occur between the pixel electrode 101 and the counter electrode 103.

On the other hand, the signal supplied to the source bus line which is an output signal line of the binary driver is always “H” (high level signal for selecting black display) or “L” (white display is selected). Low level signal) is fixed to either signal. Therefore, if a signal that is inverted at a constant cycle as described above is applied to the counter electrode 103, for example, as shown in FIG. 5B, the source bus line Sn and the counter electrode 103 The potential difference between them varies. Here, in the example shown in FIG. 5B, the voltage applied to the liquid crystal interposed between the source bus line Sn and the counter electrode 103, that is, the liquid crystal applied voltage repeats 0V and 5V. . For this reason, flicker is caused between the source bus line Sn and the counter electrode 103 due to a change in potential difference.

Therefore, if the potential difference between the source bus line Sn and the counter electrode 103 varies, flicker occurs, and it may be visible regardless of the presence or absence of a black matrix, resulting in a problem of lowering display quality. .

The present invention has been made in view of the above-described problems, and its object is to suppress flicker generated between the source bus line and the counter electrode, so that whether or not there is a black matrix on the source bus line. Accordingly, an object of the present invention is to provide a liquid crystal display device with high display quality in which flicker is not visible.

In order to solve the above problems, in a liquid crystal display device in which a liquid crystal capacitor is sealed between an active matrix substrate and a counter substrate, the active matrix substrate includes a plurality of data signal lines and a plurality of scanning signal lines. Pixel electrodes arranged in a matrix corresponding to the intersecting portions are formed, and the counter substrate is opposed to the pixel electrode of the active matrix substrate, and the counter voltage is synchronized with the voltage applied to the pixel electrode. Is applied to the liquid crystal capacitor, and a period in which a voltage corresponding to a video signal supplied to the data signal wiring is applied to the pixel electrode is a video signal writing period, and a next video signal writing period. When the video signal non-writing period is the period until the signal signal supplied to the counter electrode with respect to the data signal wiring in the non-writing period. Signal-phase or reverse phase is characterized by being supplied.

Also, the driving method of the liquid crystal display device according to the present invention is a method of driving a liquid crystal display device in which a liquid crystal capacitor is sealed between an active matrix substrate and a counter substrate. Pixel electrodes arranged in a matrix form corresponding to the intersections with the plurality of scanning signal wirings are formed, and are applied to the pixel electrodes facing the pixel electrodes of the active matrix substrate on the counter substrate. A counter electrode that applies a counter voltage to the liquid crystal capacitor in synchronization with a voltage is formed, and a period in which a voltage corresponding to a video signal supplied to the data signal wiring is applied to the pixel electrode is a video signal writing period, When the period until the next video signal writing period is defined as the non-writing period of the video signal, the counter current is not connected to the data signal wiring during the non-writing period. It is characterized by supplying a signal of the same phase or reverse phase being supplied to.

According to the above configuration, in the non-writing period of the video signal with respect to the data signal wiring, a signal having the same or opposite phase as the signal supplied to the counter electrode is supplied to the data signal line. The potential difference between the data signal wiring and the counter electrode can be made constant. As a result, it is possible to suppress the occurrence of flicker due to the potential difference being not constant on the data signal wiring during the non-writing period, so that it is possible to suppress the display quality from being deteriorated due to the flicker.

Another liquid crystal display device of the present invention includes a first display state in which the arrangement of liquid crystal molecules is irregular when no voltage is applied between the active matrix substrate and the counter substrate, and the arrangement of liquid crystal molecules when a voltage is applied. In the liquid crystal display device in which the light diffusion type liquid crystal in the second display state that is in a regular state is sealed, a plurality of video signals for transmitting a plurality of video signals representing images to be displayed are transmitted to the active matrix substrate, respectively. Pixels arranged in a matrix corresponding to the intersections of the data signal wirings, the plurality of scanning signal wirings crossing the plurality of data signal wirings, and the intersections of the plurality of data signal wirings and the plurality of scanning signal wirings, respectively. First display data for realizing the first display state is provided on the basis of an image signal that is provided for each electrode and the pixel signal and is transmitted by the data signal wiring. And a display data storage circuit that takes in the second display data for realizing the second display state through the second supply wiring and stores the respective data. The counter substrate is formed with a counter electrode that faces the pixel electrode of the active matrix substrate and applies a counter voltage to the light diffusing liquid crystal in synchronization with a voltage applied to the pixel electrode. The period when the voltage corresponding to the supplied video signal is applied to the pixel electrode is the video signal writing period, and the period until the next video signal writing period is the video signal non-writing period. In addition, a signal having the same or opposite phase as the signal supplied to the counter electrode is supplied to the data signal wiring.

Further, the driving method of the liquid crystal display device according to the present invention includes a first display state in which the arrangement of liquid crystal molecules is irregular when no voltage is applied between the active matrix substrate and the counter substrate, and the liquid crystal molecules when the voltage is applied. A method of driving a liquid crystal display device in which light diffusing liquid crystal in a second display state in which the arrangement of the liquid crystal is in a regular state is sealed, and a plurality of images representing an image to be displayed are displayed on the active matrix substrate A plurality of data signal wirings for transmitting signals, a plurality of scanning signal wirings crossing the plurality of data signal wirings, and intersections of the plurality of data signal wirings and the plurality of scanning signal wirings, respectively. The first display state is realized based on the pixel electrodes arranged in a matrix and the video signal provided for each of the pixel electrodes and transmitted by the data signal wiring. The first display data is taken in via the first supply wiring, and the second display data for realizing the second display state is taken in via the second supply wiring, and the display data for storing the respective data And a counter electrode that is opposed to the pixel electrode of the active matrix substrate and applies a counter voltage to the light diffusion liquid crystal in synchronization with a voltage applied to the pixel electrode. A period in which a voltage corresponding to the video signal formed and applied to the data signal wiring is applied to the pixel electrode is a video signal writing period, and a period until the next video signal writing period is a video signal non-writing period. Then, in the non-writing period, a signal having the same phase or opposite phase to the signal supplied to the counter electrode is supplied to the data signal wiring.

The liquid crystal display device of the present invention includes an active matrix substrate on which pixel electrodes arranged in a matrix corresponding to intersections of a plurality of data signal lines and a plurality of scanning signal lines are formed, and the active matrix substrate A counter substrate facing the pixel electrode and formed with a counter electrode for applying a counter voltage to the liquid crystal in synchronization with a voltage applied to the pixel electrode is sealed between the active matrix substrate and the counter substrate. A period in which a voltage corresponding to a video signal supplied to the data signal wiring is applied to the pixel electrode is a video signal writing period, and a period until the next video signal writing period is a non-video signal. When the writing period is set, a signal having the same or opposite phase as the signal supplied to the counter electrode is supplied to the data signal wiring in the non-writing period. It is, in the non-write period of the video signal to the data signal lines, the relative data signal line, the signal of the signal in phase or opposite phase being supplied to the counter electrode is supplied. As a result, the potential difference between the data signal wiring and the counter electrode can be made constant, so that the occurrence of flicker due to the non-constant potential difference on the data signal wiring can be suppressed during the non-writing period. . As a result, the display quality can be prevented from being lowered due to flicker.

1 is a block diagram illustrating a schematic configuration of a liquid crystal display device according to an embodiment of the present invention. It is a schematic plan view which shows the principal part of the active area of the liquid crystal display device shown in FIG. It is a schematic block diagram of 1 pixel of the active area shown in FIG. It is a schematic sectional drawing of the active area shown in FIG. (A) is a waveform diagram showing a potential difference between a counter electrode and a pixel electrode, (b) is a conventional waveform diagram showing a potential difference between the counter electrode and a source bus line, and (c) is a counter electrode. It is a waveform diagram of the present invention showing a potential difference between the source bus line and the source bus line. FIG. 6 is a waveform diagram showing inversion periods of a counter electrode application signal Vcom, a black writing signal VA, and a white writing signal VB. FIG. 2 is a circuit diagram of a polarity controller provided in the liquid crystal display device shown in FIG. 1. FIG. 2 is a circuit diagram showing an example of a binary driver circuit provided in the liquid crystal display device shown in FIG. 1. FIG. 9 is a timing chart of various signals when driving the binary driver having the circuit configuration shown in FIG. 8. FIG. FIG. 6 is a circuit diagram showing another example of a binary driver circuit provided in the liquid crystal display device shown in FIG. 1. It is a timing chart of various signals at the time of driving the binary driver of the circuit configuration shown in FIG. It is a block diagram which shows schematic structure of the other liquid crystal display device which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail.

(Outline of liquid crystal display)
FIG. 1 is a schematic block diagram showing an example of the liquid crystal display device of the present invention.

FIG. 2 is a schematic configuration diagram of a display panel of the liquid crystal display device.

FIG. 3 is a schematic configuration diagram of one pixel of the display panel.

As shown in FIG. 1, the liquid crystal display device 1 according to the present embodiment includes a display panel 10 and a power supply 20 for driving the display panel 10.

The display panel 10 includes an active area 11, a gate driver (scanning signal wiring driving circuit) 12, a binary driver 13 (data signal wiring driving circuit), a polarity controller (signal supply circuit) 14, and a timing generator 15. The number of pixels in the active area 11 is vertical × horizontal = 320 dots × 240 dots.

In the display panel 10, as shown in FIG. 2, a pixel electrode 101 is formed through a switching element 102 at an intersection between a source bus line Sn (data signal wiring) and a gate bus line Gn (scanning signal wiring). The pixels are arranged in a matrix. In FIG. 2, a pixel memory circuit to be described later is omitted for convenience of explanation.

As shown in FIG. 3, the pixel includes a switching element 102 composed of a CMOS TFT composed of a P-type TFT and an N-type TFT provided at an intersection of a source bus line Sn and a gate bus line Gn, and the switching The memory circuit 105 is connected to the drain electrode of the element 102, and the pixel electrode 101 is connected to the output side of the memory circuit 105 via the switching element 106. A liquid crystal capacitor 104 is interposed between the pixel electrode 101 and the counter electrode 103, and a potential difference between the applied voltage of the pixel electrode 101 and the applied voltage of the counter electrode 103 is applied to the liquid crystal capacitor 104 as a liquid crystal applied voltage. ing.

In response to the output from the memory circuit 105, the switching element 106 converts a signal supplied to the pixel electrode 101 into a black writing signal (hereinafter referred to as a black writing signal VA) and a white writing signal. A signal (hereinafter referred to as a white writing signal VB) is switched.

In the pixel, the switching element 102 is turned on by the scanning signal applied to the gate bus line Gn, so that the video signal applied to the source bus line Sn is output to the memory circuit 105.

The scanning signal is applied to the gate bus line Gn by the gate driver 12, and the video signal is applied to the source bus line Sn by the binary driver 13.

The gate driver 12 applies an active scanning signal to each gate bus line based on the gate start pulse signal GSP and the gate clock signal GCK in order to sequentially select each gate bus line by one horizontal scanning period. Are repeated with one vertical scanning period as a cycle. That is, the gate driver 12 adopts a driving method in which each gate bus line Gn is sequentially selected by one horizontal scanning period.

The binary driver 13 receives the digital video signal DV, the source start pulse signal SSP, the source clock signals SCK and SCKB, and the mode signals MODE and MODEB, and applies a driving video signal to each source bus line.

The binary driver 13 is further supplied with the black writing signal VA and the white writing signal VB described above. Instead of the video signal, the black writing signal VA or the white writing signal VB is supplied to the source bus line Sn. It is designed to be applied.

The black writing signal VA and the white writing signal VB are output from the polarity controller 14. As described above, the polarity controller 14 outputs the black writing signal VA and the white writing signal VB to the active area 11 in order to apply to the pixel electrode 101.

The polarity controller 14 uses the frame signal FRAME output from the timing generator 15, the power supply VDD and the power supply VSS supplied from the power supply 20, and the counter electrode application signal Vcom, the black write signal VA, and the white write signal. A signal VB is generated. Details of the polarity controller 14 will be described later.

The timing generator 15 receives image data DAT and a display mode instruction signal M sent from the outside, generates a digital video signal DV, and outputs it to the binary driver 13.

The timing generator 15 receives the mode signal MODE, MODEB, the frame signal FRAME, the source clock (shift of the data signal line driver) from the serial data SI, the serial clock SCLK, and the serial chip select signal SCS input from the outside of the panel. Timing signals as clock signals for operating the registers) SCK / SCKB, source start pulse (horizontal period timing signal) SSP, gate clock (timing signal input to the shift register of the gate signal line driver) GCK, and gate start pulse GSP Generate.

A source start pulse SSP is supplied from the timing generator 15 to the binary driver 13, a gate clock GCK and a gate start pulse GSP are supplied from the timing generator 15 to the gate driver 12, and from the timing generator 15 to the polarity controller 14, A frame signal FRAME is supplied. The source clocks SCK and SCKB are clock signals for operating the shift register of the binary driver 13.

(Flicker measures)
As shown in FIG. 4, the display panel 10 has a liquid crystal capacitor 104 sealed between an active matrix substrate 10a and a counter substrate 10b. The active matrix substrate 10a is formed with pixel electrodes 101 arranged in a matrix corresponding to intersections of a plurality of source bus lines Sn and a plurality of gate bus lines Gn (not shown). A counter electrode 103 is formed on the counter substrate 10b so as to face the pixel electrode 101 of the active matrix substrate 10a and apply a counter voltage to the liquid crystal capacitor 104 in synchronization with a voltage applied to the pixel electrode 101. Yes.

In the display panel 10 shown in FIG. 4, since the black matrix is not provided on the source bus line Sn, flicker generated on the source bus line can be seen.

5 (a) to 5 (c) are timing charts showing potential differences between the counter electrode 103 and the pixel electrode 101 and between the counter electrode and the source bus line Sn in the non-writing period.

The pixel electrode 101 and the counter electrode 103 are applied with a signal (voltage) that is inverted at a constant period so that the liquid crystal is not deteriorated. Then, as shown in FIG. 5A, the pixel electrode 101 and the counter electrode 103 are applied with signals (in-phase signals) that are inverted at the same timing and at the same timing so as to always have a constant potential difference. ing. In the example shown in FIG. 5A, the voltage applied to the liquid crystal interposed between the pixel electrode 101 and the counter electrode 103, that is, the liquid crystal applied voltage is 0 V (white display: normally white). Case). For this reason, flicker due to a variation in potential difference does not occur between the pixel electrode 101 and the counter electrode 103.

On the other hand, the source bus line Sn which is an output signal line of the binary driver 13 is always “H” (high level signal for selecting black display) or “L” (low level signal for selecting white display). Signal) is fixed to either signal. For this reason, if a signal in which the counter electrode 103 is inverting at a constant cycle as described above is applied, as shown in FIG. 5B, between the source bus line Sn and the counter electrode 103, The potential difference fluctuates. Here, in the example shown in FIG. 5B, the voltage applied to the liquid crystal capacitor 104 interposed between the source bus line Sn and the counter electrode 103, that is, the liquid crystal applied voltage repeats 0V and 5V. become. For this reason, flicker is caused between the source bus line Sn and the counter electrode 103 due to a change in potential difference.

Therefore, in the liquid crystal display device 1 having the above configuration, as shown in FIG. 5C, a signal that makes the potential difference between the source bus line Sn and the counter electrode 103 constant is supplied to the source bus line Sn. Like to do. Here, the signal supplied to the source bus line Sn may be an in-phase signal that is inverted to the same polarity or a reverse-phase signal that is inverted to the opposite polarity at the same timing as the signal supplied to the counter electrode 103. preferable. In the present embodiment, the black writing signal VA or the white writing signal VB output from the above-described polarity controller 14 is used as such an in-phase or anti-phase signal. FIG. 5C shows an example in which the white write signal VB is supplied to the source bus line Sn. That is, the potential difference between the source bus line Sn and the counter electrode 103 is 0V, that is, the liquid crystal applied voltage is kept constant at 0V.

Here, in this embodiment, the counter electrode application signal Vcom, the black writing signal VA, and the white writing signal VB are all inverted with a width of 0V to 5V. FIG. 6 shows that the counter electrode application signal Vcom and the white writing signal VB are in phase, and the counter electrode application signal Vcom and the black writing signal VA are in opposite phases. That is, since the signal in phase with the counter electrode application signal Vcom is the white writing signal VB, as described above, the white writing signal VB is supplied to the source bus line Sn during the non-writing period. The potential difference between the electrode 103 and the source bus line Sn is kept constant (0 V).

Here, a period in which a voltage corresponding to the video signal supplied to the source bus line Sn is applied to the pixel electrode 101 is a video signal writing period, and a period until the next video signal writing period is a non-video signal. Write period.

According to the liquid crystal display device having the above configuration and the driving method thereof, during the non-writing period of the video signal with respect to the source bus line Sn, the signal supplied to the counter electrode 103 is in phase with or opposite to that of the source bus line Sn. By supplying the phase signal, the potential difference between the source bus line Sn and the counter electrode 103 can be made constant. As a result, it is possible to suppress the occurrence of flicker due to the potential difference being not constant on the source bus line Sn during the non-writing period, so that it is possible to suppress the deterioration of display quality due to the flicker.

Therefore, as shown in FIG. 4, even if the black matrix is not provided on the source bus line Sn, the potential difference between the source bus line Sn and the counter electrode 103 can be kept constant. The occurrence of flicker can be suppressed. As a result, the flicker on the source bus line Sn becomes invisible, so that deterioration of display quality due to flicker can be suppressed.

The generation of the counter electrode application signal Vcom, the black writing signal VA, and the white writing signal VB is performed by the polarity controller 14 as described above.

FIG. 7 shows a specific circuit of the polarity controller 14.

In the polarity controller 14, the frame signal FRAME is input as a control signal for the switches SW1, SW2, and SW3 corresponding to the C contacts through the buffer. The switches SW1, SW2, and SW3 are switches that sequentially output the voltages of the counter electrode application signal Vcom, the black writing signal VA, and the white writing signal VB. Each time the frame signal FRAME is switched between High and Low, the switches SW1, SW2, and SW3 select the power source so that the combination of the power source VDD, VSS, and VDD and the combination of the power source VSS, VDD, and VSS are sequentially switched. To do. Thereby, the polarity controller 14 outputs the counter electrode application signal Vcom, the black writing signal VA, and the white writing signal VB at the inversion cycle as shown in FIG.

(Description of binary driver)
FIG. 8 is a block diagram showing a schematic configuration of the binary driver 13.

FIG. 9 shows a timing chart of signals in the binary driver 13 shown in FIG.

Here, the binary driver 13 is provided with 241 shift registers, which is one stage added to 240 corresponding to the number of pixels (240) beside the active area 11. Except for the 0th stage shift register, the outputs of the 1st stage shift register to the 240th stage shift register are respectively connected to latch circuits for latching the digital video signal DV.

That is, source clock signals SCK and SCKB are input to each shift register, and outputs from the first-stage shift register to the 240th-stage shift register are connected to corresponding latch circuits. Based on the output of the shift register, the latch circuit latches the digital video signal DV and outputs it to the signal line SL <n> connected to the source bus line Sn. Here, n is an integer of 1 to 240.

Unlike the normal binary driver, the binary driver 13 switches the digital video signal DV and the white writing signal VB between the latch circuit and the signal wiring SL <n> that is the output destination. Is provided.

The switching section A is provided with a switching element composed of two CMOS TFTs in series, and switches between the digital video signal DV and the white writing signal VB. Specifically, the source electrode of the switching element in the previous stage is connected to the white writing signal VB, the two gate electrodes are connected to the mode signal MODE and the inverted mode signal MODEB, respectively, and the drain electrode is the signal wiring. Connected to SL. The output of the latch circuit is connected to the source electrode of the switching element at the subsequent stage, the two gate electrodes are connected to the mode signal MODEB and its inverted signal, the mode signal MODE, respectively, and the drain electrode is connected to the signal line SL. .

Therefore, in the switching unit A, when the mode signal MODE is at the “High” level, the mode signal MODEB is naturally at the “Low” level, so that the switching element at the front stage is turned on and the switching element at the rear stage is turned off. Become. In this case, the white writing signal VB is output to the signal line SL.

Further, when the mode signal MODE is at the “Low” level, the mode signal MODEB is at the “High” level, so that the switching element at the front stage is turned off and the switching element at the rear stage is turned on. In this case, the digital video signal DV latched by the latch circuit is output to the signal line SL.

The timing at which the mode signal MODE becomes “High” level is as shown in FIG. 9 in which data for one frame is written and data is not written until the start of data writing for the next frame (in the figure, data in the region B). The retention period is equivalent).

Since the white writing signal VB output to the signal wiring SL in this non-writing period is in phase with the counter electrode application signal Vcom as shown in FIG. 6, the source bus line Sn connected to the signal wiring SL The potential difference with the counter electrode 103 is constant. FIG. 9 shows that in the region B, the potential difference (Vcom / VB) is constant. That is, it shows that the potential difference has a relationship as shown in FIG.

In the case of the binary driver 13 shown in FIG. 8, the signal to be switched is the white writing signal VB having the same phase as the counter electrode application signal Vcom. However, as shown in FIG. It may be a black writing signal VA having a phase opposite to that of the working signal Vcom.

As described above, a high-level signal (black writing signal VA) or a low-level signal (white writing) is applied to the source bus line Sn at the timing when the writing period is switched to the non-writing period. Signal VB), a signal having the same phase (or opposite phase) as the signal supplied to the counter electrode 103 is switched and output, so that the signal between the source bus line Sn and the counter electrode 103 is output. It is possible to make the potential difference generated in step 1 constant immediately after the start of the non-writing period. As a result, the flicker generated during the non-writing period can be reliably suppressed, and the display quality can be further improved.

In addition, since the signal supplied from the polarity controller 14 to the pixel electrode 101 is a signal that is output to the source bus line Sn during the non-writing period, the signal can be shared. Accordingly, it is not necessary to separately provide a signal to be output to the source bus line Sn during the non-writing period, and the existing circuit can be used as it is, so that the manufacturing cost can be reduced and the apparatus can be downsized. It becomes possible.

In the case of the binary driver 13 shown in FIG. 8, the digital video signal DV is latched by a latch circuit using a shift register. However, the present invention is not limited to this. For example, the binary driver 113 shown in FIG. As described above, the digital video signal DV may be latched by a latch circuit without using a shift register.

In the binary driver 113 shown in FIG. 10, the digital video signal DV is divided into 80 groups (V1 to V80) of 3 each. That is, since one digital video signal DV (V1) is output to three latch circuits, three types of switching signals SSW1, SSW2, and SSW3 for the source are input to each latch circuit.

The switching signals SSW1, SSW2, and SSW3 are generated by a driver IC for driving the display panel 10 and supplied to the display panel 10 (not shown).

Note that the binary driver 113 shown in FIG. 10 also includes a switching unit C that switches between the output of the latch circuit and the white writing signal VB, similarly to the binary driver 13 shown in FIG. Since the switching unit C has the same configuration as the switching unit A shown in FIG. 8, detailed description thereof is omitted.

Also in the binary driver 113 shown in FIG. 10, as in the switching unit A of the binary driver 13 shown in FIG. 8, in the switching unit C, when the mode signal MODE is “High” level, the mode signal MODEB is naturally “Low”. Since it is “level”, the switching element at the front stage is turned on and the switching element at the rear stage is turned off. In this case, the white writing signal VB is output to the signal line SL. Further, when the mode signal MODE is at the “Low” level, the mode signal MODEB is at the “High” level, so that the preceding switching element is turned off and the succeeding switching element is turned on. In this case, the digital video signal DV (V1) latched by the latch circuit is output to the signal line SL.

As shown in FIG. 11, when the mode signal MODE becomes “High” level, the data for one frame is written, and the data is not written in until the start of data writing of the next frame (in the figure, the data in the region D). The retention period is equivalent).

Since the white writing signal VB output to the signal wiring SL in this non-writing period is in phase with the counter electrode application signal Vcom as shown in FIG. 6, the source bus line Sn connected to the signal wiring SL The potential difference with the counter electrode 103 is constant. FIG. 11 shows that in the region D, the potential difference (Vcom / VB) is constant. That is, it shows that the potential difference has a relationship as shown in FIG.

Although the present invention is effective when no black matrix is provided between the pixel electrodes 101, a black matrix may be provided. In this case, the black matrix serves to conceal the flicker so that the flicker generated on the source bus line Sn is difficult to see. However, if the black matrix is not properly arranged, the flicker may be seen. Therefore, any invention that suppresses flicker, such as the present invention, can be applied regardless of the presence or absence of a black matrix.

As described above, the present invention is particularly effective when the black matrix is not provided between the pixel electrodes 101. Therefore, the present invention is effective for a liquid crystal display device having a narrow pitch pixel arrangement in which no black matrix is provided.

In this embodiment, the liquid crystal is not particularly limited. However, for example, a light diffusion liquid crystal used in a liquid crystal display device using a display panel provided with a pixel memory circuit may be used. In particular, it is suitable for a liquid crystal display device that achieves high resolution on a display screen with a limited space such as a liquid crystal display device used for a small portable terminal.

As a liquid crystal display device using the light diffusing liquid crystal, although not shown, for example, a first display state in which liquid crystal molecules are irregularly arranged between the active matrix substrate and the counter substrate when no voltage is applied. And a light diffusing liquid crystal in a second display state in which the arrangement of liquid crystal molecules is in a regular state when a voltage is applied.

The active matrix substrate includes a plurality of data signal wirings for transmitting a plurality of video signals representing an image to be displayed, a plurality of scanning signal wirings crossing the plurality of data signal wirings, and the plurality of data Based on the pixel electrodes arranged in a matrix corresponding to the intersections of the signal wiring and the plurality of scanning signal wirings, and the video signal provided for each pixel electrode and transmitted by the data signal wiring, First display data for realizing the first display state is taken in via the first supply wiring, and second display data for realizing the second display state is taken in via the second supply wiring, A display data storage circuit for storing each data is formed.

The counter substrate is formed with a counter electrode that faces the pixel electrode of the active matrix substrate and applies a counter voltage to the light diffusion liquid crystal in synchronization with a voltage applied to the pixel electrode.

In the liquid crystal display device having the above-described configuration, the period in which a voltage corresponding to the video signal supplied to the data signal wiring is applied to the pixel electrode is similar to the liquid crystal display device having the configuration shown in FIG. When the writing period and the period until the writing period of the next video signal are set as the non-writing period of the video signal, in the non-writing period, the same phase as the signal supplied to the counter electrode with respect to the data signal wiring (or The configuration is such that a signal of the opposite phase is supplied.

According to the above configuration, in the non-writing period of the video signal to the data signal wiring, a signal having the same phase (or opposite phase) as that of the signal supplied to the counter electrode is supplied to the data signal line. Thus, the potential difference between the data signal wiring and the counter electrode can be made constant. As a result, it is possible to suppress the occurrence of flicker due to the potential difference being not constant on the data signal wiring during the non-writing period, so that it is possible to suppress the display quality from being deteriorated due to the flicker.

In the present embodiment, as described above, the gate driver 12 employs a driving method in which each gate bus line is sequentially selected by one horizontal scanning period.

However, the present invention is not limited to the line sequential drive type gate driver as described above, but can be applied to a liquid crystal display device employing a line address drive type gate driver that selectively drives only the gate lines that need to be rewritten. .

FIG. 12 shows a liquid crystal display device 1 having a gate driver that employs a line address driving method.

Here, the configuration of the liquid crystal display device 1 shown in FIG. 12 is almost the same as that of the liquid crystal display device 1 shown in FIG. 1, and the signal input to the gate driver 12 is changed. That is, in FIG. 1, the gate start pulse signal GSP and the gate clock signal GCK are input from the timing generator 15 to the gate driver 12, whereas in FIG. GSEL is input.

The signal GEN and the signal GSEL are generated by decoding address data indicating position information of a pixel electrode to which a video signal is written from the serial data SI. The signal GEN and a decoding circuit that generates the signal GSEL are arranged in the timing generator 15.

Here, the signal GEN indicates a signal for controlling a period during which the gate bus line is selected. For example, the gate bus line Gn selected by the address becomes active during the signal GEN = “High”, the pixel connected to the gate bus line Gn opens, and the data from the source bus line Sn is captured. During the signal GEN = “Low”, all lines are inactive. The signal GSEL is a signal obtained by decoding the input address.

As described above, in the liquid crystal display device 1 shown in FIG. 12, the gate driver 12 selectively drives the gate bus line Gn in accordance with the position information of the pixel electrode to which the video signal is to be written. That is, only the gate bus line Gn that needs to be rewritten is driven.

Therefore, only the gate bus line Gn connected to the pixel electrode that needs to be rewritten is selectively driven, so that the non-writing period can be made longer than in the above-described line sequential driving method.

This makes it possible to stably adjust the potential difference between the source bus line Sn and the counter electrode during the non-writing period, so that the occurrence of flicker during the non-writing period can be reliably suppressed.

As described above, in the liquid crystal display device 1 shown in FIGS. 1 and 12, in the display panel 10, the black writing signal VA, the white writing signal VB, the mode signal MODE, the mode signal MODEB, and the counter electrode application signal are provided. Although an example in which Vcom is generated inside the display panel 10 has been shown, the present invention is not limited to this, and it may be generated by a driver IC provided outside the display panel 10.

Further, as the data signal wiring driving circuit for driving the data signal wiring, a binary driver that outputs either a high level signal or a low level signal to the data signal wiring is provided, and the binary driver is provided. Is in phase with the signal supplied to the counter electrode from either a high-level signal or a low-level signal at the timing when the data signal wiring is switched from the writing period to the non-writing period. Or it is preferable to switch to a reverse phase and output.

According to the above configuration, the binary driver causes the data signal wiring to be switched from the high level signal or the low level signal to the counter electrode at the timing of switching from the writing period to the non-writing period. Since a signal having the same phase or opposite phase to the supplied signal is switched and outputted, the potential difference generated between the data signal wiring and the counter electrode can be made constant immediately after the start of the non-writing period. As a result, flicker occurring during the non-writing period can be reliably suppressed, and the display quality can be further improved.

In addition, a signal supply circuit that supplies a signal in phase or opposite phase to a signal applied to the counter electrode to the pixel electrode is provided, and the binary driver receives a signal supplied from the signal supply circuit to the pixel electrode, It is preferable that the signal be output to the data signal wiring during the non-writing period.

According to the above configuration, the signal supplied from the signal supply circuit to the pixel electrode is a signal output to the data signal wiring in the non-writing period, so that the signal can be shared. As a result, it is not necessary to separately provide a signal to be output to the data signal wiring during the non-writing period, and the existing circuit can be used as it is, so that the manufacturing cost can be reduced and the apparatus can be downsized. It becomes.

In addition, a scanning signal line driving circuit for driving the scanning signal wiring is provided, and the scanning signal line driving circuit selectively drives the scanning signal wiring according to position information of a pixel electrode to which a video signal is written. It is preferable to do.

Accordingly, only the scanning signal wiring connected to the pixel electrode that needs to be rewritten is selectively driven, so that the non-writing period is made longer than the driving method in which each scanning signal wiring is sequentially selected by one horizontal scanning period. be able to.

Furthermore, the liquid crystal display device having the above configuration can be applied to various electronic devices. For example, it is preferably mounted on a liquid crystal television in which improvement in display quality is essential. Further, it may be used as a monitor for a personal computer. If the liquid crystal display device of the present invention is used as an electronic device provided with a display device, display with high display quality without flicker is always performed. It becomes possible to make it.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope shown in the claims, and the embodiment can be obtained by appropriately combining the technical means disclosed in the embodiment. Is also included in the technical scope of the present invention.

The present invention can be used for all liquid crystal display devices in which the potential difference between the counter electrode and the pixel electrode is a liquid crystal applied voltage, and in particular, a liquid crystal in which the pixel pitch is narrow and the black matrix is not provided on the data signal wiring. The present invention can be used for a display device and an electronic device including the display device.

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 10 Display panel 11 Active area 12 Gate driver (scanning signal wiring drive circuit)
13 Binary driver (data signal wiring drive circuit)
14 polarity controller 15 timing generator 20 power supply 101 pixel electrode 102 switching element 103 counter electrode 104 liquid crystal capacitor 105 memory circuit Sn source bus line (data signal wiring)
Gn gate bus line (scanning signal wiring)
DAT Image data DV Digital video signal VA Black writing signal VB White writing signal Vcom Counter electrode application signal

Claims

In a liquid crystal display device in which a liquid crystal capacitor is sealed between an active matrix substrate and a counter substrate,
The active matrix substrate is formed with pixel electrodes arranged in a matrix corresponding to the intersections of the plurality of data signal wirings and the plurality of scanning signal wirings,
The counter substrate is formed with a counter electrode that faces the pixel electrode of the active matrix substrate and applies a counter voltage to the liquid crystal capacitor in synchronization with a voltage applied to the pixel electrode.
When a period corresponding to the video signal supplied to the data signal wiring is applied to the pixel electrode is a video signal writing period and a period until the next video signal writing period is a video signal non-writing period ,
In the non-writing period, a signal having the same phase or opposite phase to the signal supplied to the counter electrode is supplied to the data signal wiring.
As the data signal wiring driving circuit for driving the data signal wiring, a binary driver for outputting either a high level signal or a low level signal to the data signal wiring is provided.
The above binary driver
At the timing when the data signal wiring is switched from the writing period to the non-writing period, either the high level signal or the low level signal is in phase with or opposite to the signal supplied to the counter electrode. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is switched to a phase signal for output.
A signal supply circuit for supplying a signal in phase or opposite phase to the signal applied to the counter electrode to the pixel electrode;
3. The liquid crystal display device according to claim 2, wherein the binary driver uses a signal supplied to the pixel electrode from the signal supply circuit as a signal output to a data signal line in the non-writing period.
Between the active matrix substrate and the counter substrate, a first display state where the arrangement of liquid crystal molecules is irregular when no voltage is applied, and a second display state where the arrangement of liquid crystal molecules is regular when a voltage is applied In a liquid crystal display device in which a light diffusion type liquid crystal is sealed,
In the active matrix substrate,
A plurality of data signal wirings for respectively transmitting a plurality of video signals representing images to be displayed;
A plurality of scanning signal wirings crossing the plurality of data signal wirings;
Pixel electrodes arranged in a matrix corresponding to the intersections of the plurality of data signal lines and the plurality of scanning signal lines,
Based on a video signal provided for each of the pixel electrodes and transmitted by the data signal wiring, the first display data for realizing the first display state is taken in via the first supply wiring and the first A second display data for realizing two display states is taken in via the second supply wiring, and a display data storage circuit for storing each data is formed,
In the counter substrate,
A counter electrode is formed opposite to the pixel electrode of the active matrix substrate and applying a counter voltage to the light diffusion liquid crystal in synchronization with a voltage applied to the pixel electrode.
When the video signal writing period is the period in which the voltage corresponding to the video signal supplied to the data signal wiring is applied to the pixel electrode, and the period until the next video signal writing period is the non-writing period of the video signal ,
In the non-writing period, a signal having the same phase or opposite phase to the signal supplied to the counter electrode is supplied to the data signal wiring.
A scanning signal wiring drive circuit for driving the scanning signal wiring;
The scanning signal wiring driving circuit is
5. The liquid crystal display device according to claim 1, wherein the scanning signal wiring is selectively driven in accordance with position information of a pixel electrode to which a video signal is to be written.
In a driving method of a liquid crystal display device in which a liquid crystal capacitor is sealed between an active matrix substrate and a counter substrate,
The active matrix substrate is formed with pixel electrodes arranged in a matrix corresponding to the intersections of the plurality of data signal wirings and the plurality of scanning signal wirings,
The counter substrate is formed with a counter electrode that faces the pixel electrode of the active matrix substrate and applies a counter voltage to the liquid crystal capacitor in synchronization with a voltage applied to the pixel electrode.
When a period corresponding to the video signal supplied to the data signal wiring is applied to the pixel electrode is a video signal writing period and a period until the next video signal writing period is a video signal non-writing period ,
A method for driving a liquid crystal display device, comprising: supplying a signal having the same phase or a reverse phase to a signal supplied to the counter electrode to the data signal wiring during the non-writing period.
Between the active matrix substrate and the counter substrate, a first display state where the arrangement of liquid crystal molecules is irregular when no voltage is applied, and a second display state where the arrangement of liquid crystal molecules is regular when a voltage is applied A method of driving a liquid crystal display device in which a light diffusion type liquid crystal is sealed,
The active matrix substrate includes a plurality of data signal wirings for transmitting a plurality of video signals representing an image to be displayed, a plurality of scanning signal wirings crossing the plurality of data signal wirings, and the plurality of data Based on the pixel electrodes arranged in a matrix corresponding to the intersections of the signal wiring and the plurality of scanning signal wirings, and the video signal provided for each pixel electrode and transmitted by the data signal wiring, First display data for realizing the first display state is taken in via the first supply wiring, and second display data for realizing the second display state is taken in via the second supply wiring, A display data storage circuit for storing each data is formed,
The counter substrate is provided with a counter electrode that faces the pixel electrode of the active matrix substrate and applies a counter voltage to the light diffusion liquid crystal in synchronization with a voltage applied to the pixel electrode.
When the video signal writing period is the period in which the voltage corresponding to the video signal supplied to the data signal wiring is applied to the pixel electrode, and the period until the next video signal writing period is the non-writing period of the video signal ,
A driving method of a liquid crystal display device, wherein a signal having the same phase or a reverse phase as a signal supplied to the counter electrode is supplied to the data signal wiring during the non-writing period.
Electronic equipment comprising the liquid crystal display device according to claim 1 or 4.